1. Technical Field of the Invention
The present invention relates in general to the telecommunications field and, in particular, to a method and system for managing radio base station (RBS) resources in a cellular communications network.
2. Description of Related Art
The radio air interface of the upcoming third generation mobile communication systems is presently being defined by the standardization committees of the European Telecommunications Standards Institute (ETSI) and the International Telecommunications Union (ITU). The ETSI third generation system is called the Universal Mobile Telephone System (UMTS), while the ITU system is called the International Mobile Telephone 2000 (IMT 2000). FIG. 1 is a diagram that illustrates the nodes or network elements and certain interfaces in a third generation cellular radio network (e.g., UMTS) as presently defined by the ETSI.
In accordance with the ETSI definition, the network 100 shown in FIG. 1 includes a mobile station 102 connected to one or more base stations 104a-n and/or 105a-n by a call control interface Uu 103. Each base station 104a-n and 105a-n is connected to a radio network controller (RNC) 106 or 108 by a respective traffic control interface Iub 107a-n or 109a-n. The RNCs 106 and 108 are connected to each other by an RNC interface Iur 110, and to a mobile services switching center (MSC) 112 by a respective traffic control interface Iu 111 and 113. The traffic control interfaces Iub 107a-n and 109a-n function primarily for ordering the BSs to set up radio connections to one or more MSs.
In addition to the interfaces shown in FIG. 1, which are used for call control, connection control, and radio network control, the network 100 also includes interfaces (not shown) used for management of the resources of the network and the nodes. As such, the term xe2x80x9cmanagementxe2x80x9d in this context includes all of the control functions that are not directly related to the handling of calls and connections, such as, for example, network and network element configuration, fault and alarm supervision, performance monitoring, and collection of performance statistics data.
The ETSI has decided that the interfaces shown in FIG. 1 shall be standardized, so that it will be possible for a cellular network operator to purchase the network nodes (BSs, RNCs, MSC) from different system manufacturers (vendors). The process of standardizing the Iu, Iur and Iub traffic control interfaces has already begun. As such, these interfaces are based on known techniques, which have also been used for the Global System for Mobile Communications (GSM). All messages to be transferred over these interfaces are defined in the pertinent standard.
FIG. 2 is a diagram that illustrates a significant problem that exists for the developing third generation systems. Essentially, the problem is how to design the management interfaces, Mu, so that the management of a network with different vendors"" BSs will be efficient. FIG. 2 shows a portion of the network 100 in FIG. 1 but in more detail. As shown in this illustrative example, the BSs 104a and 104b are from two different vendors and connected to another vendor""s RNC (106). These connections have been made possible because the Iub interfaces 107a and 107b to the RNC 106 have been standardized and are exactly the same for both BSs. However, as described in more detail below, the management interfaces, Mub1 (116a) and Mub2 (116b), to a network operation center (e.g., Base Station Manager or BSM) 114 cannot be completely standardized. The above-described problem is further complicated, because the BSM 114 is from yet another different vendor.
For example, the messages to be transferred over the management interfaces, Mub, fall into two different categories: (1) standardized messages, which are used for the management of implementation-independent xe2x80x9cmanaged objectsxe2x80x9d; and (2) vendor-specific messages, which are used for configuration, supervision and monitoring of the internal system components of the BSs, such as, for example, processors and switches. Currently, these messages cannot be specified in a standard, because the system components are implemented differently in the different vendors"" BSs (and also in different types of BSs from a same vendor). One conclusion that can be made is that the interfaces, Mub1 (116a) and Mub2 (116b), can be used to transfer both standardized and vendor-specific messages. As such, each such Mub interface has one part that can be standardized, and one part that is different for BSs from different vendors.
Clearly, the network architecture shown in FIG. 2 has a fundamental problem, in that the Mub interfaces between the BSs (104a and 104b) and the BSM 114 are not completely standardized. Also, some of the messages to be conveyed over these management interfaces are vendor-specific. Consequently, it is virtually impossible to design one xe2x80x9cstate of the artxe2x80x9d BSM that can handle the management of BSs of all different vendors.
A possible solution to the problem of non-standardized interfaces between such nodes is to split the Mub interfaces so that the standardized messages are sent to a common BSM, while the non-standard messages are sent to BSMs that are designed specifically for each type of BS provided by different system vendors. As such, what can be considered a xe2x80x9cstate of the artxe2x80x9d third generation cellular network architecture is shown in FIG. 3.
FIG. 3 is a diagram that illustrates a proposed standard architecture for a third generation cellular network referred to as the UMTS Terrestrial Radio Access Network (UTRAN). The proposed UTRAN network management architecture shown in FIG. 3 includes a BSM System 115 in a multi-vendor UTRAN environment. The BSM System 115 includes a common BSMcommon 114 from vendor 4, a different BSM1 118 from vendor 1, and yet another different BSM2 120 from vendor 2. As shown, the main difference between the architectures shown in FIGS. 2 and 3 is that FIG. 3 splits the Mub interfaces so that the standardized messages are sent to a common BSM, while the non-standard messages are sent to the different vendors"" BSMs. In other words, non-standard messages are sent between the BS 104a and the vendor-specific BSM1 118, and between the BS 104b and the vendor-specific BSM2 120 via the management interfaces Mub1 116a and Mub2 116b, respectively. The standard messages are sent between the two BSs 104a and 104b and the common BSMcommon 114 via the management interfaces Mub1 116a and Mub2 116b, respectively, and then split off and sent via a standard management interface Mubstandard 117 to the common BSMcommon 114.
FIG. 4 is a diagram that illustrates an existing Base Station Subsystem (BSS) management architecture for the GSM in a multi-vendor environment. Clearly, the proposed UTRAN BSM management architecture shown in FIG. 3 is much more advanced than the GSM BSS management architecture shown in FIG. 4. For example, a GSM Abis interface contains both a standardized call handling interface (comparable to Iub in FIG. 3) and a management interface (comparable to Mub). However, the GSM network architecture is not very efficient, because the two BSMs (BSM1, BSM2) shown in FIG. 4 must be implemented in the BSC node and it is not possible to implement them separately (unlike the configuration shown in FIG. 3).
The GSM management architecture shown in FIG. 4 has severe shortcomings. For example, as a practical matter, it is virtually impossible to connect different vendors"" BSs to the same BSC (similar to an RNC in the UMTS). The reason for this shortcoming is that most cellular equipment manufacturers have designed their GSM systems so that the BSMs for their respective BSs are executed on a proprietary (non-standard) computer system. In most cases, this proprietary computer system is the same one used for the traffic control functions in the BSC. Consequently, it is virtually impossible for a manufacturer to implement a structure based on the architecture shown in FIG. 4. As such, one vendor""s BSM cannot be executed in a different vendor""s BSC.
The ETSI UMTS expert group has suggested that the management interface, Mub, should be specified as an interface separate from the Iub. If implemented, that suggestion would improve the equipment compatibility problem considerably as compared to the GSM solution. As such, the architecture shown in FIG. 3 could then be implemented. The functional entities, BSM1 (118) and BSM2 (120), could then be implemented as completely separate nodes that could use any computer system. However, the architecture shown in FIG. 3 indicates that a certain degree of coordination will be needed so that the common management functions can be implemented in a uniform way.
The problem area that the present invention provides a solution for relates to the practical problem of trying to integrate, in a common processing system, the program modules that implement the functional entities BSMcommon, BSM1, BSM2, etc. (e.g., one BSM for each type of BS). However, as mentioned earlier, as a practical matter, it is virtually impossible to accomplish the requisite equipment integration in the existing GSM architecture, because incompatible computer systems are used in the different vendors"" BSCs. The UMTS management architecture currently being discussed in the ETSI will likely improve the situation, but there are still a number of significant problems that remain to be resolved.
For example, if each BSM in a xe2x80x9cBSM Systemxe2x80x9d is to be run in a separate computer, the cost of such a system will be relatively high. Furthermore, it is difficult to provide a uniform user interface for such a system comprising several computers, where each such computer is running a BSM for a specific type of BS. As another example, in order to be able to integrate BSMs from different vendors into one system, as shown in FIG. 3, the software modules have to be executable in the same computer. In principle, it should be possible to define a standard execution environment (e.g., Windows, Unix, etc.) for a BSM System, but this alternative is not realistic at the present time. Specifically, most GSM operators already use network management systems, and typically, they also want to use these existing systems for managing future UMTS networks. Moreover, the ETSI does not standardize implementation platforms, so it should not be readily assumed that it will be possible to implement an integrated base station management system, such as the one shown in FIG. 3. However, as described in detail below, the present invention successfully resolves the above-described problems.
In accordance with a preferred embodiment of the present invention, a method and system are provided for implementing management functions on both sides of a BSM interface (i.e., in both the BSM and the BS) so that a plurality of different types of BSs can be managed by the same BSM. The management service functions are allocated to the specific BS involved. As such, each type of BS can maintain all of the software needed to perform the base station management services (e.g., element management services). Consequently, one common BSM can be used for the management of any type of BS. In other words, the BSM can be considered as a generic BSM. In accordance with the teachings of the present invention, any BS can be connected to the generic BSM via an Mub interface.
An important technical advantage of the present invention is that a single base station manager can be used for management of all types of base stations.
Another important technical advantage of the present invention is that cellular operators can achieve efficient management of their radio access network, even if the network is composed of different types of base stations.
Yet another important technical advantage of the present invention is that base stations can be implemented differently in one cellular network in order to be optimized for different capacity requirements, such as base stations for macro-cells, micro-cells and pico-cells.
Still another important technical advantage of the present invention is that a cellular network operator can utilize base stations from different vendors using different system architectures (e.g., processors, switches, etc.).
Still another important technical advantage of the present invention is that a management system operator can log-in to a base station from any computer connected to a management data communication network.